Made a quick Excel thing to compare the space forces rating and SCI WU costs of two fleets in combat.

Others may find this useful, to guesstimate the outcome of a particular engagement based on SCI WU costs (as suggested by WTV) rather than the space forces rating, which can be unreliable.

Not exactly comprehensive: it doesn't account for missile-based ships vs. missile-protected ships, for example. It also doesn't include every ship type, just the most commonly used to attack/defend. I did this to test the outcome of a specific scenario: the Hegemony's entire jumpfleet vs. the defenses I can muster up at the capital. Turns out the results were quite... unfavorable.

This is an interesting approach. Because combat is a complex interaction, we have not yet discovered a good rule of thumb for predicting the outcome of an engagement. In particular, since Era 3 it is clear that defenses are significantly stronger than their per-unit costs. They still "feel" underpowered to mature empires because there is no way to accumulate them in sufficient numbers to deflect an entire empire's fleet. For incoming players (I have been experimenting with this a little) planetary defenses remain intimidating for quite a while. In a short-format game, if such a thing existed, I think planetary defenses would play a HUGE role.

There are a couple big problems with SCI WU costs that I need to address if I want to come up with a single metric for directly comparing true unit costs:

They all need to be recalculated to reflect "abundant" raw material deposits since this seems to be how game mechanics (e.g. Mesophon cost) now treats them and most players try to get abundant deposits where available. A better name for them then would be "minimum SCI WU costs" which is a mouthful. In practice every unit's cost to build is slightly different

They don't reflect unit halfLife which has a HUGE effect on how many units are actually present at any given time. In practice something like a starcruiser is much more cost effective than SCI WU makes it appear to be.